bcopy() and it is marked as LEGACY in IEEE Std 1003.1-2004 (``POSIX.1'')
New programs should use: memmove() if you can guarantee that the input
and output buffer do not overlap, then memcpy() would be more efficient.
Note that bcopy() takes its src and dst arguments in the opposite order
from memcpy() and memmove().

Please avoid using "you", and this sentence is weird. The original has some trailing whitespace, too (please check with igor -R, which will check for those and other problems). Showing the suggested functions as .Xr references would be more helpful to the reader:

New programs should use
.Xr memmove 3 .
If the input and output buffers do not overlap,
.Xr memcpy 3
is more efficient.